Nonlinear effects on magnetic energy release by forced magnetic reconnection: Long wavelength perturbations
Abstract
Two-dimensional, nonlinear magnetohydrodynamic simulations in a compressible plasma to investigate magnetic energy release during the process of forced magnetic reconnection are carried out. This is in order to study the heating of the Sun's corona where it is believed that reconnection is induced by the photospheric motions. A sheared force-free field is perturbed by a transitory slow disturbance (pulse) at the boundary. This disturbance triggers the formation of a current sheet that subsequently releases stored magnetic energy through magnetic reconnection. Previously, it has been shown that for small boundary perturbations, the simulation results are consistent with the previous analytic theory based on a linear approach. For larger amplitude perturbations, or close to the threshold for tearing instability, the evolution shows nonlinear behavior. Solar coronal heating may arise due to a series of reconnection events, and a primary aim of this work is to study the interaction of such heating events. Thus, the perturbations are applied at the boundary by successive pulses. It is found that following the second driving pulse, the current sheet expands along the separatrix before relaxing to a reconnective equilibrium with magnetic islands and releasing even more magnetic energy for the same amplitude perturbation. Here, the previous work is extended to study long wavelength perturbations for which the system exhibits even stronger nonlinear aspects.
- Publication:
-
Physics of Plasmas
- Pub Date:
- May 2006
- DOI:
- 10.1063/1.2200630
- Bibcode:
- 2006PhPl...13e2902J
- Keywords:
-
- 52.35.Vd;
- 52.35.Mw;
- 52.65.Kj;
- 52.35.Py;
- 96.60.Iv;
- 96.60.Mz;
- Magnetic reconnection;
- Nonlinear phenomena: waves wave propagation and other interactions;
- Magnetohydrodynamic and fluid equation;
- Macroinstabilities;
- Magnetic reconnection;
- Photosphere